


My Onee-chan!

by Metallicity



Category: BanG Dream! (Anime), BanG Dream! Girl's Band Party! (Video Game)
Genre: Alpha/Beta/Omega Dynamics, Bondage, Cunnilingus, Ew, F/F, Incest, Knifeplay, Mating Cycles/In Heat, Non-Consensual Bondage, Rape/Non-con Elements, Rutting, Sibling Incest, Torture, Underage Rape/Non-con
Language: English
Status: Completed
Published: 2020-08-16
Updated: 2020-08-16
Packaged: 2021-03-05 22:20:29
Rating: Explicit
Warnings: Rape/Non-Con, Underage
Chapters: 1
Words: 8,789
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/25932766
Author URL: https://archiveofourown.org/users/Metallicity/pseuds/Metallicity
Summary: Sayo and Hina watch a game show together.
Relationships: Hikawa Hina/Hikawa Sayo
Comments: 18
Kudos: 68





	My Onee-chan!

**Author's Note:**

  * For [tsuugusayo](https://archiveofourown.org/users/tsuugusayo/gifts), [sayohjna](https://archiveofourown.org/users/sayohjna/gifts).



> A few days back, a valued member of the SayoHina community, tsuugusayo, posted a sizeable SayoHina one-shot to the archive. Now, the work had some scary tags like "Torture", "Knifeplay", and "Non-Consensual Bondage", but I figured there was no reason not to at least give it a shot. And if it turned out tsuugusayo's degeneracy was too great for me, I could always just stop reading the work.
> 
> Unfortunately, due to what could only be a tragic copy-paste accident, it appeared that the entire work had been erased and replaced with gibberish. Since then, all of tsuugusayo's works, including their various other sibling incest one-shots, have been removed from the archive, which I can only imagine was due to embarrassment over this mistake. I was disappointed to not have any new SayoHina to read, but more so I was sad for tsuugusayo, who had clearly cared so much to write this in the first place.
> 
> So, I resolved I would try to recreate a work that could live up to tsuugusayo's original vision. I'm not quite up to the depravity some of the tags imply, so I've played a bit fast and loose with how I incorporated the original tags, but hopefully I'll have captured at least something tsuugusayo can be proud to say they inspired.
> 
> As a side note, judging by the name "tsuugusayo", I worked under the assumption that the "Ew" tag was supposed to stand in for the "Hazawa Tsugumi/Hikawa Sayo" tag. I have hedged slightly by making this only appear in a small part of the story, but apologies in advance if this was not actually the case.
> 
> Also sayohjna if you're reading this, I love you unconditionally.

Sayo glanced forlornly at her phone once more as she unlocked the front door. It was already ten past eight. Hina might still be sitting in her room waiting for her, whining impatiently, but more likely she had already gotten bored and  _ started without her _ . She could almost imagine her sister, lying back on the couch, moaning “Onee-chan” into the empty house, as she was forced to entertain herself until Sayo arrived.

Everything had lined up perfectly. Their parents were both out for the night, Hina didn’t have to go into the studio, and her practice was supposed to have wrapped up an hour ago. If only Udagawa-san hadn’t insisted on fooling around on the drums so much. Minato-san had made everyone go over that same section a dozen times, before switching her anger over to Sayo for not demanding the same thing right along with her.

Not that she would have been able to explain why she was so desperate for practice to end on time tonight of all nights. It was hard enough to admit to herself that she wanted to get closer to Hina. Letting someone else know, even another band member, that she was doing something  _ like that _ with her sister, that she was even looking forward to it, was just too horrifying to consider.

The living room was empty. Not entirely surprising, but Sayo had half expected to see Hina lying back on the couch, one eye towards the door, waiting to catch her sister sneaking inside. Though Sayo couldn’t really hide that she was late at this point. It was probably best to just go up to Hina’s room and face the music, as they said. It wasn’t Sayo’s fault she was late, not entirely, but Hina was hard to reason with at the best of times, and anything that involved her “Onee-chan” she was particularly unyielding with. Not that Sayo would have her any other way. Not anymore.

Not wanting to waste any more time, Sayo headed up the stairs, but paused as she was reaching Hina’s door. There was a strange muttering from the other side, clearly Hina’s voice, but different enough to hold Sayo just shy of knocking on the door. It took a moment to place, but there was a clear hint of anger. Sayo tried to recall a single instance where her sister had been legitimately angry with her, angry with anyone really, but came up short. What could possibly have happened?

Sayo couldn’t imagine it was just because she was late, but then she couldn’t imagine much of anything that would explain what was going on. Though the prospect terrified her a bit more than Sayo was quite willing to admit, it seemed she needed to get a direct answer

_ Knock, Knock _

The muttering cut out, as if someone had finally found Hina’s off switch mid-sentence. Then, after a moment’s silence, Sayo decided to call out.

“Hina? Are you in there?”

She felt slightly ridiculous even asking such an obvious question, but she tried to err on the side of politeness. It had definitely broken Hina out of whatever trance she had fallen into, since Sayo soon heard the more familiar noises of Hina quickly attempting to tidy up her room just before she would open the door.

Then there was a far less familiar scraping sound.

No, Sayo recognized it, it was the same exact sound as when Hina tried to move her bed into Sayo’s room a few weeks after they had gotten their own rooms, all those years ago. What the hell was going on in there?

Sayo nearly made up her mind to open the door herself and find out, when she finally heard Hina bounding towards the door. It opened a crack, Hina’s head just poking out.

“Onee-chan, welcome home!” Hina smiled, using her body as a human barricade to prevent the door from opening any further. “I know you probably don’t want to be bothered right now, so you can feel free to head off to your room and practice!”

Hina let out a somewhat pained laugh, gave a slight wave, and then slammed the door in Sayo’s face.

Sayo stared at the closed door in front of her.

What the fuck was that?

Though it was considered by many to be a fool’s errand, Sayo once more found herself trying to process the existence that was Hikawa Hina. While her sister’s actions were never what one might call  _ predictable _ , there was usually at least a thin thread of logic that Sayo could find to attempt to unravel the rest. Generally, she relied on the fact that Hina loved Sayo more than anyone else in the world. That Hina would never be the one to forget what was supposed to happen tonight of all nights. It’s not like this had even been Sayo’s idea in the first place!

Waiting a brief moment for her blush to die back down, Sayo steeled herself. She was going to find out what was going on with her sister, and no stupid door was getting in her way!

_ Click, Click _

Locked?

Sayo tried the door knob once more, but it refused to turn in the slightest. Behind the door, Sayo could make out the sound of a window sliding open. It was possible Hina had decided at that moment that it was too hot in her room. If it wasn’t the middle of winter, maybe.

_ Knock! Knock! Knock! _

“Hina! Whatever the hell you’re doing in there, give it up and get out here!”

Sayo didn’t hear the sound of the window closing, but she also couldn’t hear any signs of a Hina-sized mass hitting their front lawn, so her sister probably had ceased any plans of escape she might have been enacting. Not that Sayo could think of a reason why Hina would need to escape at this moment.

Then, in one fluid motion, too fast for Sayo to register entirely before it was over, Hina unlocked the door, pulled it open, then slammed it behind her.

“Did you need something, Onee-chan?”

Hina tilted her head to one side as she asked, a slightly dazed look on her face, still with one hand behind her back holding the door shut tight.

“While there are many things I feel the unfortunate need to ask you right now,” Sayo paused, taking a brief moment to peek at her lock screen, “it’s already a quarter past eight and I don’t want to waste any more time than we already have.”

“Eh? Wasting time?” Hina’s eyes suddenly widened. “Wait! You said eight o’clock? It’s Wednesday? We’re late!”

Hina then jumped down the entire flight of stairs down to the first floor, landing in a somersault that somehow failed to knock over any of the plants nearby. At least, not enough to cause any noticeable damage. Sayo just shook her head and followed after her sister, who was already running into the living room.

Sayo heard the familiar buzz of the TV coming to life, cutting off for a brief instant as Hina navigated to the right station. By the time Sayo made it down the stairs, she saw Hina already sprawled over the couch, taking up all the cushions, as usual. The first few nights Sayo had tried to fight for a solitary cushion of her own, but it always ended up with Hina sneaking over and lying on her lap by the end of night. Now Sayo simply let her do as she pleased from the start, it was easier that way.

As Hina lifted her head to let Sayo sit down, the commercial break ended and a familiar host came on, interviewing one of the night’s contestants. Hina had talked her into watching this new game show a few months back, and while she had had her reservations at first, the craziness slowly grew on her, and she had started to look forward to the days where she and Hina could just lie back on the couch and not have to worry about school, bands, idols, or whatever problems in their relationship they were still working out.

It wasn’t the sort of show that one would proudly admit to watching, with a peculiar mix of nonsensical rules and low-brow humor that Hina delighted in and their parents despised. But the host had a sort of magnetism to him that drew you in, even as he described the strangest of tasks the contestants would have to complete. Not unlike Hina, in a way, projecting herself so blindingly bright that it hardly mattered what she was actually saying.

Sayo let out a brief giggle, causing Hina to turn up from her lap pillow.

“What’s so funny, Onee-chan?”

It hadn’t been quite long enough for Hina to have fallen asleep, but the way she snapped into focus just then made it clear she hadn’t been giving the show her full attention. Whatever chaos she’d been dealing with earlier, it must have been a bit exhausting.

“I was just thinking that Hina would do a great job hosting a show like this. You’re already quite comfortable up on stage, and I don’t think too many of your fans would be shocked by the career change.”

“Onee-chan, you’re a genius!” Hina’s eyes lit up, and she jumped to her feet.

Sayo gave a weak smile as she tried to not let her sister’s choice of words sting too much.

“I always wanted to be on a game show, but when PasuPare finally got our own challenges to do, it turned out to be way too easy. None of the challenges turned out to be as hard as people made it look on TV. But if I were the host, I could come up with my own challenges, and make them extra boppin’!”

Sayo wasn’t too sure that game show hosts were really too involved with actually coming up with material for the show, but she couldn’t help but smile at the gleam in her sister’s eyes. She stood up behind Hina and wrapped her arms around her sister’s neck.

“I’m sure you would at least stand out as the only host who refused to do their own challenges because they were  _ too easy _ .”

Hina took a moment to lean back, forcing the pair to collapse back onto the couch.

“Never give an order you aren’t willing to carry out yourself! Isn’t that the true spirit of leadership, Onee-chan?”

Sayo gave a brief giggle as Hina snuggled deeper into her chest. She was usually restrained in her physical affection, but when Sayo gave an inch, Hina took a mile. And Sayo wouldn’t have it any other way, if she were honest for a moment.

They stayed together like that as the hour drew on, the final challenge was revealed, and ultimately their game show was replaced by an infomercial displaying a knife set of some sort. Nothing the twins had any interest in, both aware to varying degrees of their limits in the kitchen, but they continued to lay there all the same, as Hina started to drift off in Sayo’s arms.

It wouldn’t be long before their mother would be home, and while the most incriminating evidence was now lost to time, she still wouldn’t be pleased to see the girls up this late watching TV, regardless of what was on. And so, Sayo grabbed the remote, switched back over to a less suspicious channel, and then hit the power button. All that was left to deal with was the dead weight resting on top of her.

Sayo knew from experience that it could be difficult to wake Hina up when she got like this, but ultimately Hina was only a high school girl. She had a slight weight advantage over most of the heavier equipment she had to move while preparing for live shows, but nothing that Sayo couldn’t handle once she had Hina settled properly in her arms.

The stairs were an annoyance, however, and Sayo had to put Hina down for a moment once they had reached the top. Her sister began to stir slightly as Sayo was catching her breath.

“Onee-chan?” Hina mumbled, with one eye half open, “What time is it?”

“Go back to sleep Hina, we’re nearly back to your room already.”

Hina gave a small nod, eyes still mostly closed, and resigned herself to her sister’s care. But as Sayo bent down to pick Hina up once again, she rolled out of the way, narrowly missing the corner of the stairwell, and came to a stop leaning over the last few steps, much more awake than before.

“My room? What are we going there for?”

“It’s nearly ten, Hina, we’re going to bed.”

Hina pulled herself into an upright position in defiance of gravity and mechanical advantage alike, and quickly sprang to her feet.

“Then I want to go to bed with Onee-chan tonight! My room is no good!”

Before Sayo could protest, she found herself being carried to her own room instead. Hina ran down the hallway as if the added weight wasn’t even there, and burst into Sayo’s room with practiced ease. Hina lazily threw her twin onto the bed, before jumping on top of her.

“Ah! Isn’t this the best, Onee-chan?” Hina asked, curling around Sayo.

“Not that I don’t appreciate this, Hina, but we aren’t exactly ready for bed.”

Hina paused for a second, staring down at their school uniforms, which neither girl had bothered to change out of. She sat up and scratched the back of her head.

“I guess you’re right Onee-chan, I was just getting ahead of myself.”

Hina was already out the door and rushing to the bathroom down the hall by the time Sayo finally managed to get her bearings and head out towards the other bathroom. She puzzled over Hina’s strange behavior tonight as she brushed her teeth, but was no closer to an answer by the time she was ready to head back.

As Sayo was about to open the door to her room, she noticed Hina heading back to her own room. Which was an odd move, after insisting so loudly that there was something wrong with it. Exactly  _ what _ was wrong was anyone’s guess, of course.

“Hina?” Sayo called from down the hall, as she walked towards her sister, “Did you change your mind? I thought you said your room was ‘no good’.”

Sayo gave a strange emphasis when echoing Hina’s words that even she couldn’t mistake as anything other than suspicion.

“Huh? Oh yeah! I forgot, my room is,” Hina chuckled nervously for a moment, taking special care to place herself between her sister and the door, “It’s really messy right now. I just can’t deal with it, there’s just no way. So please let me sleep with you tonight!”

Hina knelt down and hugged her sister’s legs as she pleaded. She wasn’t quite in tears, but Sayo wouldn’t have blamed anyone less familiar with her sister for believing she was.

“As long as you promise you’ll clean everything up in the morning.”

Sayo spoke before she even really thought about what she was saying. Why was she even trying to extract such a promise? Shouldn’t she be insisting that Hina stop these games and just explain what was actually wrong?

But a quick “Boppin’!” from Hina was all the warning Sayo had before her sister grabbed her hand and all but dragged the pair back to Sayo’s door. Once inside, Hina dropped Sayo’s hand, and immediately began to unbutton her top.

“Eh? Hina! What are you doing?”

Hina quit undressing for a moment to give her sister a quick glance, but Sayo seemed to be refusing to look her in the eyes.

“We’re getting ready for bed, right? We can’t sleep in our uniforms, Onee-chan!”

It was at this moment that Sayo came to the realization that neither of them owned anything approaching sleepwear. It had been years since Sayo had spent the night at a friend’s house, and anything she might have worn then would be almost pitifully small on her now. As for Hina, she had shown no reservations over stripping in front of another girl, so any overnights with the rest of PasuPare probably went about the same, no sleepwear necessary.

“At least keep your underwear on,” Sayo eventually asked, trying not to think too hard about whether Hina usually slept entirely naked. But that thought was soon buried by the notion that she too was still wearing her school uniform.

There were a few Roselia t-shirts in her closet (and even a PasuPare t-shirt Hina had forced upon her), but going down that route almost felt like it was conceding something. Sisters should feel comfortable enough with each other not to worry about such things, and certainly not harbor any untoward thoughts about sleeping in the same bed. Hina clearly had no problem in such attire, what might she think of Sayo if she insisted on wearing a t-shirt to bed, when she was just fine in her underwear alone on any other night?

Even as Sayo thought this through to herself, she didn’t quite believe it. In the back of her mind, her reasoning was entirely different, and these conscious thoughts were merely the excuses used to justify what she had already decided to do.

“Onee-chan! Hurry up! Why are you just standing there?” Hina called from the bed, clad in only a plain white bra. And presumably panties as well, though only her upper body was visible from under the covers.

Looking down at herself, and the folded pieces of her uniform, it turned out that what Sayo had really wanted was to strip in front of her sister as well. Not wanting to stand there half in shock for any longer than it turned out she already had been, Sayo climbed into bed next to Hina, her sister pulling the covers over the two of them.

It should have been a feeling of safety, warm under the sheets and blankets, lying next to her twin sister who loved her with all her heart. And if she was to be honest for a moment, who Sayo loved in return just as much. But the problem came when Sayo chose to be honest with herself for more than a moment.

Hina was so close.

The reality of her sister slowly drifting to sleep beside her, half naked in bed with Sayo, was doing wonders for Sayo’s honesty. But far from a calming effect, it left Sayo too filled with nervous energy to even risk touching Hina. Cuddling together on the couch, fully clothed, was one matter, but now in the dead of night, the thought of pure skin to skin contact managed to horrify Sayo ever so slightly more than it tempted her.

And fuck, did Hina tempt her, resting beside her without a care in the world. Unaware of all the thoughts that were buzzing around in Sayo’s head. All the thoughts that had been in her head for far too long now, that she should have never let leak out to this extent.

Sayo was paralyzed, refusing to act on her impulses, yet unable to quell those impulses so she could finally rest. It wasn’t long before she heard her mother come home, but it was far longer before her father eventually followed suit. All the while, a minor panic began to spread through Sayo.

Her parents weren’t Hina, they wouldn’t be blinded by a desire to get closer to Sayo, they would see this supposed bonding moment for what it really was. Or at the very least, question why Sayo had so easily succumbed to Hina’s whim instead of doing what was proper. And those questions were nearly as bad as the truth itself, when Sayo herself struggled to come up with a convincing answer. A convincing lie, at least.

But mother and father alike went straight to bed, checking neither of their children’s beds, and in all likelihood morning would prove no different. At least for the night, Sayo was safe. Or rather, had remained unseen, allowed to live on as she had been for another day.

It must have been nearing midnight by now, but Sayo was no closer to falling asleep. Though all the dangers of the day had come to rest, Sayo couldn’t help but stare at Hina, lying peacefully in the dim light of far off street lamps. Her sister was turned away from her, as if hiding from Sayo’s gaze, but just the hints of her exposed shoulder, and the way Hina’s bra straps were curving around her body, were doing wild things to Sayo’s imagination.

She could almost hear her sister begging for more, even if Sayo hadn’t even begun to think what she might like to be doing to Hina. And that moan of “Onee-chan” sounded—extremely real.

Sayo shook her head. She must have been hearing simply what she wanted to hear. There’s no way that Hina would be calling for her sister while masturbating, the fact that it appealed so strongly to her fantasies was all but proof that she had fallen a bit too deep into those fantasies.

As another moan came up from the twists of sheets and flesh before her, however, it became much harder to deny that, at the very least, Hina was definitely masturbating. Right next to her sister. While they were in bed with nothing but their underwear.

Or, taking a closer look at how Hina’s bra had started to ride up, perhaps not even that. And Sayo definitely wanted to take a closer look. The slight, yet steady rhythm of Hina’s shoulder as it shifted in a small circular motion was a clear hint of what was happening as Hina’s arm trailed under the covers and into obscurity. If her increased panting alone hadn’t already given such things away.

“Hina.”

It had come out as nothing but a pained whimper, but to Sayo’s growing horror it had come out nonetheless. She was immediately aware that one of her hands had come to rest just over her own panties. It wasn’t providing any particular stimulation, but it had only taken that small push for Sayo’s brain to decide to abandon all notions such as “common sense”, or “consequences”.

“Onee-chan!” Hina moaned, in belated response, a fair deal louder, and unmistakable this time. She continued on, and for a brief moment Sayo allowed herself to believe Hina hadn’t heard her at all. Then, everything stopped.

“Eh? Onee-chan?”

Hina shot up from her trance, sitting up and staring directly at Sayo. Her bra was lifted up over her breasts, and Sayo couldn’t help but take her sister in at that moment. Hina’s assets were a fair bit more generous than her sister’s, Sayo wasn’t even sure one could fit into her hand. She also couldn’t believe that she could just reach up and find out. If she had been far braver than she currently felt, at least. She really needed to stop staring at her sister’s tits right now.

Pretending to be asleep was probably a lost cause at this point, but Sayo might just manage to pull off pretending to be a girl who didn’t want to fuck her sister. She’d managed it for this long, at the very least.

“Hina? What are you doing still awake?”

Sayo immediately gave an internal curse after she spoke. She hadn’t wanted to focus on Hina’s activities, but nobody could have mistaken what she had been doing. And not acknowledging that her sister had her breasts exposed had to be suspicious even on whatever bizarre lines of thought were going through Hina’s brain at this moment.

“Onee-chan, I. I was just,” Hina began, belatedly noticing that she should be covering her chest, and raising her hands up to hide her deliciously erect nipples from Sayo’s view. Sayo could have sworn she had stopped staring.

“You were just masturbating next to your sister?”

Sayo decided it was best to just not mince words at this point. Focus on the facts, and not on all the terrible feelings that were rising up inside her right now.

“Onee-chan is so mean!”

Hina lifted her arms up as if to feign crying, but aborted mid-motion when she remembered why her hands were placed where they were. She then just allowed herself to collapse against the headboard, hands at her sides, head staring down into her still bare chest.

“It’s Onee-chan’s fault I’m like this, anyway,” she whispered.

No, Hina. Please don’t say something like that.

Don’t so plainly state the truth of the matter.

Sayo had failed as a sister. Pushed boundaries when she thought she could get away with it. Stole touches where she thought it was safe. And now she had created this horny, desperate mess that was the sexiest sight she’d ever laid eyes on. She was still staring at her sister.

“If Onee-chan hadn’t acted so sexy and zappin’ all the time, maybe Tsugu-chan wouldn’t have,” Hina’s blush grew as her thoughts finally caught up to her words, “Wouldn’t have...”

“Hazawa-san?”

It was almost absurd. Sayo had felt completely trapped as her sister’s naked body arched over her, helpless but to take in every inch. Unable to avoid noticing how her hips lacked any hint of cloth from the panties she recalled seeing earlier, just enough skin poking out from under the sheets for there to be no doubt.

And then Hina started talking about Hazawa-san? What did such a plain, unremarkable girl like her have to do with Hina’s current state? Why would she have any relation to how Hina’s breath continued to follow an unsteady rhythm, how beads of sweat were so tantalizingly outlining the curves of her body?

Sayo finally averted her eyes, looking down at the sheets between the two of them, trying to allow rational thought to return as she attempted to unravel Hina’s words. No longer distracted by her sister’s naked form, the answer seemed obvious.

Hazawa-san was perhaps the only person one could point to as a true overlap in Sayo and Hina’s circles of friends. The only person who could know both of them well enough to tell that something was off. The only one who could notice that their interactions had been changing. The only one who could tell Hina that her sister was in love with her.

And apparently Hina had been  _ receptive _ to that fact. Though hopefully she hadn’t made that so clear in front of Hazawa-san herself.

Sayo climbed up to her sister’s level, ignoring her attempts to stumble through a non-answer, finally able to look Hina in the eyes once more. She gently rested her hands on her sister’s bare shoulders.

“I don’t care what Hazawa-san said right now, Hina. I want you to hear the truth from me,” Sayo took a breath before continuing. “Right now, I can’t imagine things turning out to be anything other than an absolute disaster after tonight. But given that’s the case, I think I’d like to spend at least one night with the girl I love the most in the entire world.”

Hina’s confused cry of “Onee-chan!?” was swiftly silenced as Sayo’s lips pressed up against hers. Sayo hadn’t been forceful with her first kiss, but neither had she hesitated. Caution was the territory of girls who hadn’t yet resolved to fuck their sisters and damn the consequences.

Kissing Hina was, in a word, bliss. Gone were the guilty stealing of touches, of covert glances, in the moments when she thought her sister wasn’t paying attention. She was allowed to simply enjoy the pleasure of being completely open with Hina, and her sister responding in kind. She reveled in the sensation of Hina’s lips parting for the first time, being able to explore her sister’s mouth. She was finally free to continue far beyond the point where she would have crushed such fantasies in her own mind.

Sayo let one of her hand’s slide downward, tracing the curve of Hina’s breast. Cupping it in her hand, as she had not dared earlier, was almost surreal. And it did fit in her hand after all, for the most part. To say it fit perfectly would be more poetic, if slightly less accurate. But for Sayo, simply feeling her sister moan against her lips as she squeezed was perfection enough.

Another hand soon followed the first, and as Sayo grew bolder, she began to tease at Hina’s nipples. Just brushing up against them at first, but soon the desperate need to elicit new and exciting noises from her sister took over, and she started rubbing, and pinching, and twisting, and delighting in all the pleasure she was pushing upon Hina. She felt her panties start to stick to her body with damp lust as Hina whimpered out another pitiful “Onee-chan”.

Sayo felt a sudden rush of motion, and found herself with her back against the sheets, Hina’s hands pressed down on her shoulders, Hina’s breasts hanging freely over her own. She must have removed her bra entirely while Sayo had been wrapped up in the heat of things, since her sister’s upper body was now entirely exposed. Or more accurately, risking a brief glimpse down to confirm her earlier suspicions, her sister was pressing down on top of her, 100% completely naked. The moment before Hina finally spoke was enough to drive Sayo absolutely wild with need.

“It’s unfair! Onee-chan has been doing so many zappin’ things, but she’s still in her underwear. Hina should get to do the same things to Onee-chan!”

All Sayo’s lust-addled brain could do at this point was nod and accept the logic of her sister’s argument, so she reached her arms behind her to undo the clasps of her bra. As if she could actually hear the moment the final clasps had come undone, Hina immediately tore away Sayo’s bra with a half whispered “Boppin’”.

Hina drank in the sight of her sister’s exposed body, and Sayo felt a new heat build up inside her. Hina had been largely passive during Sayo’s exploration of her body, receptive to her kisses and touches, but never taking the initiative. But as Sayo felt Hina’s hot lips close around her nipple, she soon discovered why.

As amazing as it had been to finally let loose her urges upon her sister, there was something simply sublime in lying back and allowing Hina to completely dictate her pleasure. She wasn’t entirely sure if she could have moved even if she wanted to. The dull pleasure of a hand kneading into her breast sapped her remaining strength and made Hina’s gentle weight on top of her far too oppressive to overcome.

“Hina!”

Sayo let out something between a moan and a scream, and definitely far too loud. Their parents should be asleep by now, but Sayo didn’t want to chance them waking up. She forced her lusts out in heavy pants, sometimes breaking into a whine, but hopefully less audible than before.

Hina gave her sister no time to recover, pressing her teeth down into the painfully stiff flesh of her sister’s nipple. Her free hand stroked down her side, teasing lower and lower as it crossed her abdomen and met one final barrier. Sayo’s panties were entirely soaked in need for her sister’s touch, but with Sayo’s help, Hina managed to slide them down past her thighs and then off around her feet entirely.

The motion had forced Hina to abandon her sister’s breasts, but she didn’t see this as a setback so much as an opportunity. Placing an arm against each of her sister’s thighs, she pushed outward and exposed Sayo’s glistening sex to the winter’s night air. Hina looked up towards her sister, lying back and stealing this short moment to catch her breath.

“It looks like you need some help down here, Onee-chan!” Hina giggled, running a single finger down one side of her sister’s entrance. Sayo cried out weakly as the sensation of her sister’s touch eventually caught up to her momentary exhaustion.

“Don’t tease me like this, Hina. Please,” Sayo begged, almost unable to believe what she was asking for. Who she was asking it from.

Hina relished in the sounds of Sayo’s pleads, before relenting, leaning forward and placing her hands to spread her sister open before her. Sayo suppressed a groan as she first felt her sister’s tongue slip between her folds. Her strokes started languid, easing Sayo down into a sea of pleasure, then grew in intensity until she felt no hope of surfacing. Drowning in the sensations her sister was giving her, was that how Sayo had chosen to go out?

Burying her fingers into Hina’s mint green hair, pulling her into closer, it seemed that Sayo had made her decision. She held fast as each flick of Hina’s tongue against her clit pulled her down deeper and deeper. She felt so much, yet could barely even think.

And then it was over.

“Eh?”

Sayo tried to sit up, but it had been such an effort to even voice her surprise. Hina climbed up on top of her and greeted her sister with a brief kiss.

“We won’t be able to do this with our parents home, if that’s how loud you are when you cum, Onee-chan!” Hina giggled, sneaking in a few kisses along Sayo’s collarbone.

Loud? Had she been loud? She could vaguely recall screaming her sister’s name right at the end, but the memory was fuzzy. As if it had been a completely different Sayo, when she had been at the peak of her pleasure. Surely Hina couldn’t blame her for that Sayo’s actions. Not when it was all because Hina’s tongue had been... so incredible.

“How are you so good at everything, Hina?” Sayo whined, leaning into her sister’s kisses as she slowly trailed up her neck. “I’m still not even sure I would be able to figure out half of what you just did.”

Hina wrapped her arms around her sister, and twisted the two of them into a seated position.

“I’m sure you’d do great Onee-chan!”

Hina took Sayo’s hands into her own, staring into her eyes with the absolute faith that Hina held solely for her twin.

“It mostly just takes a bit of practice at first,” Hina laughed nervously, “It’s no different from learning how to do anything else, really!”

Practice? What  _ practice _ ?

Sayo’s thoughts turned back to earlier that night, when Hina had started to strip down right in front of her. Maybe she was giving her sister’s restraint too much credit when she assumed Hina had only gone as far as that with her bandmates as well. PasuPare had always been rather open in their affection, who was to say what could have happened behind closed doors?

She tried to imagine Hina learning what she had done just now with Maruyama-san or Shirasagi-san. She didn’t like the emotions that were surfacing. She squeezed her sister’s hands tighter.

“Hina, I don’t know who it was you  _ practiced _ with, but you’re mine now, okay?” Sayo blushed, not as mentally prepared to ask all this as she wished. “And if you want to do something like this. If you want to do that, you have to do it with me!”

Hina just laughed under her sister’s intense gaze.

“Don’t worry so much, Onee-chan. You’re the one I love the most, after all. Shouldn’t you know I’d only do something like that with another girl if it was an emergency?”

Of course. It was an emergency. Sayo was just being mindlessly jealous, when there were certainly many reasonable explanations as to why her sister had eaten out another girl before. An emergency. That made sense.

Sayo let out a sigh, as the girls allowed their hands to part. She was beginning to remember why she was so content to stay ignorant of Hina’s personal life. Hina wasn’t just a strange girl, she was also a girl that strange things happened around. An emergency? What sort of B-grade eroge event was that?

It was probably best to smile and take Hina at her word. Even her sister wouldn’t do something so absurd as to come up with a lie like this.

“So do you want to try it, Onee-chan?”

“Eh? Try what?”

Hina leaned back on the wall that Sayo’s bed was pressed up against, and casually showed off her near inhuman flexibility as she lifted her feet into the air, spreading her legs wide to cover nearly the entire length of the bed. And spreading other areas as well in the process, which weren’t covered in the slightest.

“You know, practice! I promise it will be totally boppin’!”

Sayo studied her sister’s exposed and waiting body, more hesitant now than she had been all night. She wasn’t Hina. She couldn’t just come across some sort of bizarre sexual “emergency” one time and suddenly know exactly how best to please a woman. Hina did have a point that practice was necessary to improve, as if her sister of all people needed to tell her that, but that didn’t help her much if she wanted to  _ perform _ at her best this same night.

Sayo wasn’t nearly as optimistic as her sister that they would have ample time to improve together. That they would ever allow this to happen again after tonight. She couldn’t afford to waste this chance simply working to do better “next time”. She needed to do everything in her power to make sure tonight was special for Hina as well, since it would probably be her only chance.

Shaking off such depressing thoughts, Sayo smiled at her sister as she leaned up against her, taking a moment to enjoy the pressure of their chests pressing together.

“I think for tonight,” Sayo whispered into her sister’s ear, “I’ll stick with something I’m a bit more familiar with.”

She kissed Hina’s ear, and then allowed a hand to drop towards Hina’s core. Sayo’s fingers found easy entrance, Hina’s legs spread so wide, her sex absolutely dripping from everything that had happened tonight. Poor Hina, to have been teased so much and have so little to show for it.

Sayo was much more comfortable with this. She had plenty of experience in how to get a woman off with her fingers, even if it had never been  _ another _ woman. But the frequency with which she thought of Hina in those moments must count for something as well, right?

At the very least, it beat the hell out of trying to figure out whatever it was Hina had done with her tongue. Sayo hadn’t been in the best frame of mind to be taking notes at the time.

As she rubbed small circles into her sister’s clit, Sayo decided it wouldn’t hurt to be a little more adventurous. After all, Hina had demonstrated so many other ways Sayo could use her mouth. And those tits were simply begging for attention, as they swayed under Hina’s ragged breathing.

Hina squealed as her sister bit down hard on her nipple, nothing like the careful teasing she had given Sayo earlier. But the pain had a delicious flavor to it, and Sayo had sense enough to not do any lasting damage. Sayo then lapped at the nipple with her tongue, washing away the memory of the bite in gentle waves of pleasure.

Sayo continued her two front war on her sister’s senses, but it seemed that Hina wasn’t quite as out of it as Sayo had been. Starting as mere teasing brushes against Sayo’s inner thigh, Hina’s fingers soon snaked their way up and plunged deep into Sayo’s folds.

Sayo took the shock of this surprise attack out on Hina’s poor, abused nipple, directing her moans inward as she sucked on it with all the force she could muster. Hina’s fingers felt wonderful inside her, but not enough to distract Sayo from her goal. It would be unfair to take things this far and not ensure Hina came just as hard as she had. Yes, a rather wicked idea in the back of Sayo’s mind agreed, such a thing would be so very cruel.

Sayo relented on Hina’s nipple, looking up into Hina’s face, eyes closed in absolute bliss.

“Are you close, Hina?” Sayo asked, once again whispering into her sister’s ear.

“Ah! Yes, Onee-chan! Please!”

“Please?” Sayo laughed, “Whatever could you be asking for, I wonder.”

Sayo pulled her fingers back and began to trace almost lazily around Hina’s lower lips, providing just enough stimulation to ensure Hina wouldn’t be able to entirely think straight.

“Stop it, Onee-chan! You’re so mean!” Hina whined. ”Just let me cum already! Please!”

“I’m not sure Hina. How could I just let a girl like you cum, when—” Sayo paused, drawing a blank on anything that Hina would actually refuse to do for her sister. And forget anything she might struggle to do, not with how determined she would be here.

In fact, there was only one instance Sayo could recall where Hina had ever even come close to defying her. But she supposed, for this purpose, once was enough.

“How could I let such a girl cum when she won’t even admit what she was doing in her room before I got home?”

Sayo gave a rather vicious grin, accentuating the end of her question with a sharp pinch to Hina’s clit. Her sister made such beautiful noises. And so diligent too, still working her sister up to a second orgasm with her fingers even as she was being so terribly teased. Hina might have been brazen, but even she probably would feel some shame from admitting to masturbating to thoughts of her own sister. If she didn’t care, why had she tried so hard to hide it?

“Onee-chan please! Do I have too?”

The way Hina was begging so pitifully was bringing Sayo dangerously close to the edge. She needed to end this quickly, and so began to redouble her efforts on Hina’s clit. Her fingers rubbed out tight circles, over and over, focusing on bringing Hina up once more to her previous heights.

“Of course you don’t have to cum Hina. If you don’t want to tell me, all you have to do is say so.”

Sayo then shoved two fingers inside Hina, attempting to find a rhythm that would continue to build Hina’s pleasure without finishing things before she intended. But it seemed like this final push was enough to break Hina’s resolve.

“I was punishing Tsugu-chan!” Hina cried out, closing her eyes and preparing to accept whatever Sayo would decide to do to her next.

“Oh? It’s even worse than I expected?” Sayo asked lazily, nearly lost in the sensation of Hina’s fingers drawing out her own climax. “How naughty of you, to do such things to another girl right under your sister’s nose. Should I even let you cum?”

“Yes! Please Onee-chan! I’m so close!” Hina cried, nearly as lost as her sister.

“I guess I should reward your honesty,” Sayo admitted, “after making such a demand.”

It was quickly growing difficult for Sayo to remember that she needed to keep moving her fingers, as her second orgasm grew so very close. Matching the rhythm of Hina’s own fingers inside of her, Sayo leaned up against Hina and forced them into a kiss as they pleasured one another.

The buildup of emotion and sensation was starting to get too much for Sayo. The friction of Hina’s fingers as they penetrated deep within her sex. The way Hina’s walls squeezed around her own fingers. Hina kissing her. Hina punishing another girl in her room? If something seemed out of place, Sayo was far too gone to care.

Sayo wasn’t entirely clear which of them came first, but she recalled how many moans of pleasure were stifled as their lips continued to press together, forcing so many different feelings upon one another. At least she didn’t shout out Hina’s name this time. She was fairly certain.

Lying back on her bed, Sayo pulled Hina into an embrace. So much had happened tonight, so much that Sayo needed quite a bit of time to properly process. But for now she was content to just hold Hina in her arms and forget about all her worries.

Is what she would like to say.

There was a concept that Sayo didn’t quite know the word for, if it was named at all. The feeling of looking on events with fresh eyes after orgasm, when the mind was no longer clouded by arousal. That humans were willing to accept or go along with certain things while aroused that no longer made sense to them when re-examined after the fact.

Sayo felt no regret from having slept with Hina. She was scared for the future, and wasn’t entirely sure she had made the right decision for herself or her sister. But she was glad to have finally expressed her feelings. Even in the sober light of their afterglow, Sayo could not entirely fault the decisions she had made tonight.

But there was one rather concerning notion that remained.

“Hina?”

Hina lifted her head out of Sayo’s chest, looking up at her sister.

“Yeah Onee-chan?”

“What the hell did you mean when you said you were ‘punishing’ Hazawa-san?”

“Eh he he.” Hina chuckled, rubbing the back of her head, trying her best to hide her nervousness.

“Don’t ‘eh he he’ me Hina! What is that possibly supposed to mean?”

Hina blinked, before pouting at her sister.

“I guess it means exactly what you think it means. But this is all Onee-chan’s fault anyway!”

Those words again. Sayo felt a hint of shame rise up inside her, before she tried to fully understand what Hina had said. Sayo’s fault? That Hina had apparently trapped Hazawa-san inside her room and started doing god knows what to her?

And, thinking on it a bit longer, Hazawa-san was probably still in Hina’s room right this moment. Possibly still awake even, and had just listened to Sayo having sex with the girl who had effectively kidnapped her.

Calling this a B-grade eroge event was simply an insult to eroge.

“How the hell is this my fault? I don’t remember giving any indication I would support this sort of madness, much less instigating it! I thought both of us got along quite well with Hazawa-san.”

“That’s just the problem Onee-chan!” Hina pointed an accusatory finger, “You’re too nice! Tsugu-chan couldn’t help but fall in love with you!”

Sayo never expected someone would complain that she was too nice, but acting surprised about that would be somewhat burying the lead.

“Fall in love with me? Hazawa-san?” Sayo asked her sister, mostly rhetorically, as she watched puzzle pieces starting to fall into place. And what a terrifying picture they made when put together.

“It’s that time of the year, and Tsugu-chan saw you as the perfect target to unleash all her twisted desires upon. She had a love letter written up and everything! There’s no way I could allow her to go after Onee-chan like that!”

Sayo tried to connect the image of Hazawa-san in her mind with anything approaching ‘twisted desires’, but her mind nearly short circuited in the attempt. Regardless, this sort of thing was a perfectly natural biological response, and didn’t reflect on Hazawa-san as a person. But all the same, it was hard to believe that the girl had anything too sinister planned when her first move had apparently been to write Sayo a love letter.

“So to ‘protect’ me, you cornered Hazawa-san in a back alley—”

“Hey!” Hina objected, “I invited her over and she showed up quite willingly!”

“I apologize, that was my mistake. So to ‘protect’ me, you abused Hazawa-san’s trust—”

No response from Hina this time.

“—and then tied her up in your room and ‘punished’ her in an attempt to get her to stop being in love with me?”

Hina glared at her sister, not entirely appreciating the derisive tone Sayo was taking on. Hina had been concerned for her sister’s safety and purity! She couldn’t just stand by and do nothing.

“It could have worked!” Hina protested, ignoring her sister’s incredulous look, “If Tsugu-chan was really just going after you because she had too much pent up lust that she lacked an outlet for, all I had to do was provide that outlet!”

It did make sense, in a crazy Hina sort of manner. But the “could have worked” concerned Sayo. Which probably meant that Hazawa-san hadn’t decided she was in love with Sayo simply so they could have sex when she was in need. Even if Hina had fully satisfied her lusts (which after tonight wasn’t too hard to believe), that wouldn’t just make someone fall out of love.

“How was I supposed to know she was such a kinky bitch!” Hina complained, burying her face in Sayo’s chest once more.

Sayo waited a beat, hoping that Hina would expand upon this thought. Or more honestly, hoping that Hina would admit that she misspoke somehow.

“You’ve lost me.”

“I tried my best Onee-chan! I really did. I teased her breasts mercilessly, I ate her out for the better part of half an hour, I even took some toys out of my collection! Nothing worked. Even after I noticed she was getting off a bit from being tied up, none of the punishments I could come up with would phase her. She was even laughing towards the end.”

Sayo couldn’t help but pat Hina’s shoulder as she cried, even as her mind had fallen hopelessly behind trying to comprehend the words Hina was saying. Then Hina climbed out of her arms, hints of tears still in her eyes, and she picked something up off the floor.

“See! I even tried asking Tomoe-chan for help!”

Sayo looked at the screen Hina had shoved in her face:

**JoinTheAstronomyClub:** Tomoe-chan, quick! What does Tsugu-chan get off from?

**AnEternalSunset:** Hina-senpai?

**AnEternalSunset:** What’s going on?

**AnEternalSunset:** Nevermind, I really don’t want to know. Not if Tsugu is involved somehow.

**JoinTheAstronomyClub:** Please! It’s an emergency!

**AnEternalSunset:** Look, I don’t know what Tsugu talked you into, but the rest of Afterglow is very happy leaving well enough alone.

**JoinTheAstronomyClub:** Please Tomoe-chan! Just anything will help!

**AnEternalSunset:** Fine, I can say that Tsugu was talking about getting into knifeplay recently.

**AnEternalSunset:** But I don’t want to think about that any longer than I have to.

**JoinTheAstronomyClub:** Knifeplay? What’s that?

**AnEternalSunset:** It’s when someone, you know, wants to be cut up a bit. I think.

**JoinTheAstronomyClub:** Ah! I can do that! Thanks Tomoe-chan!

**AnEternalSunset:** Hina-senpai?

**AnEternalSunset:** Are you still there?

Putting Hina’s phone aside, Sayo felt more sympathy with Tomoe-san than she ever had before. She too wished she could scrub all knowledge of what she had learned about Hazawa-san in the last ten minutes from her memory. Unfortunately, that didn’t seem to be an option.

“Hina, I need you to answer something honestly for me. Is Hazawa-san slowly bleeding out in your bedroom right now?”

“Don’t worry Onee-chan!” Hina said, despite that seeming like a perfectly reasonable course of action, “I only got in touch with Tomoe-chan just before you got back! If you had been on time you probably would have seen me heading down to the kitchen!”

Sayo’s eyes narrowed.

“You weren’t going to use one of Mom’s good knives were you?”

“What?” Hina showed a brief flash of panic, “Of course I wouldn’t use something like that!”

Hina looked down for a moment.

“Which ones were those again?”

“I suppose it doesn’t matter,” Sayo started, pausing to make sure Hina was looking her in the eyes, “as long as when Mom comes downstairs tomorrow morning, there aren’t any knives missing at all.”

Hina gave a defeated nod.

“Now, why don’t we go to sleep. We’ll need to wake up bright and early tomorrow. I seem to recall you promising that you would clean up your  _ very messy room _ in the morning.”

Hina gave a cute glare, but ultimately relented and settled in under the covers once more. Curling up beside her sister in bed, Sayo finally allowed herself to relax for a moment. It seemed as though she had been completely right about tonight, when the truth had finally been laid out.

Hina’s motives were easy enough to understand, after a fashion. If you knew she loved Sayo more than anyone else in the world.

And without a doubt, tomorrow was going to turn out to be an absolute disaster.

**Author's Note:**

> For anyone reading this who didn't happen to be poking around certain tags on 14 Aug 2020, I want to clarify that tsuugusayo's work in question contained only the notes "you're actually fucking disgusting for clicking on this LMAOOOO stan sayotsugu fuck you freaks ❤️❤️" and "get help❤️❤️❤️", with the work itself being nothing by the phrase "fictional incest is unfunny because it normalizes and glorifies real incest ❤️" repeated for slightly under the length of this work.
> 
> tsuugusayo was kind of a dick.


End file.
